messages.c

video linux conference

/*****************************************************************************
 * messages.c: messages interface
 * This library provides an interface to the message queue to be used by other
 * modules, especially intf modules. See config.h for output configuration.
 *****************************************************************************
 * Copyright (C) 1998-2004 VideoLAN
 * $Id: messages.c 10710 2005-04-17 12:58:33Z sigmunau $
 *
 * Authors: Vincent Seguin <[e-mail]>
 *          Samuel Hocevar <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/
#include <stdio.h>                                               /* required */
#include <stdarg.h>                                       /* va_list for BSD */
#include <stdlib.h>                                              /* malloc() */
#include <string.h>                                            /* strerror() */

#include <vlc/vlc.h>

#ifdef HAVE_FCNTL_H
#   include <fcntl.h>                  /* O_CREAT, O_TRUNC, O_WRONLY, O_SYNC */
#endif

#include <errno.h>                                                  /* errno */

#ifdef HAVE_UNISTD_H
#   include <unistd.h>                                   /* close(), write() */
#endif

#include "vlc_interface.h"

/*****************************************************************************
 * Local macros
 *****************************************************************************/
#if defined(HAVE_VA_COPY)
#   define vlc_va_copy(dest,src) va_copy(dest,src)
#elif defined(HAVE___VA_COPY)
#   define vlc_va_copy(dest,src) __va_copy(dest,src)
#else
#   define vlc_va_copy(dest,src) (dest)=(src)
#endif

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static void QueueMsg ( vlc_object_t *, int , const char *,
                       const char *, va_list );
static void FlushMsg ( msg_bank_t * );
static void PrintMsg ( vlc_object_t *, msg_item_t * );

/**
 * Initialize messages interface
 *
 * This functions has to be called before any call to other msg_* functions.
 * It set up the locks and the message queue if it is used.
 */
void __msg_Create( vlc_object_t *p_this )
{
    /* Message queue initialization */
    vlc_mutex_init( p_this, &p_this->p_libvlc->msg_bank.lock );

    p_this->p_libvlc->msg_bank.b_configured = VLC_FALSE;
    p_this->p_libvlc->msg_bank.b_overflow = VLC_FALSE;

    p_this->p_libvlc->msg_bank.i_start = 0;
    p_this->p_libvlc->msg_bank.i_stop = 0;

    p_this->p_libvlc->msg_bank.i_sub = 0;
    p_this->p_libvlc->msg_bank.pp_sub = NULL;

#ifdef UNDER_CE
    p_this->p_libvlc->msg_bank.logfile =
        CreateFile( L"vlc-log.txt", GENERIC_WRITE,
                    FILE_SHARE_READ|FILE_SHARE_WRITE, NULL,
                    CREATE_ALWAYS, 0, NULL );
    SetFilePointer( p_this->p_libvlc->msg_bank.logfile, 0, NULL, FILE_END );
#endif
}

/**
 * Flush the message queue
 */
void __msg_Flush( vlc_object_t *p_this )
{
    int i_index;

    vlc_mutex_lock( &p_this->p_libvlc->msg_bank.lock );

    p_this->p_libvlc->msg_bank.b_configured = VLC_TRUE;

    for( i_index = p_this->p_libvlc->msg_bank.i_start;
         i_index != p_this->p_libvlc->msg_bank.i_stop;
         i_index = (i_index+1) % VLC_MSG_QSIZE )
    {
        PrintMsg( p_this, &p_this->p_libvlc->msg_bank.msg[i_index] );
    }

    FlushMsg( &p_this->p_libvlc->msg_bank );

    vlc_mutex_unlock( &p_this->p_libvlc->msg_bank.lock );
}

/**
 * Free resources allocated by msg_Create
 *
 * This functions prints all messages remaining in queue, then free all the
 * resources allocated by msg_Create.
 * No other messages interface functions should be called after this one.
 */
void __msg_Destroy( vlc_object_t *p_this )
{
    if( p_this->p_libvlc->msg_bank.i_sub )
    {
        msg_Err( p_this, "stale interface subscribers" );
    }

    /* Flush the queue */
    if( !p_this->p_libvlc->msg_bank.b_configured )
    {
        msg_Flush( p_this );
    }
    else
    {
        FlushMsg( &p_this->p_libvlc->msg_bank );
    }

#ifdef UNDER_CE
    CloseHandle( p_this->p_libvlc->msg_bank.logfile );
#endif

    /* Destroy lock */
    vlc_mutex_destroy( &p_this->p_libvlc->msg_bank.lock );
}

/**
 * Subscribe to the message queue.
 */
msg_subscription_t *__msg_Subscribe( vlc_object_t *p_this )
{
    msg_bank_t *p_bank = &p_this->p_libvlc->msg_bank;
    msg_subscription_t *p_sub = malloc( sizeof( msg_subscription_t ) );

    vlc_mutex_lock( &p_bank->lock );

    /* Add subscription to the list */
    INSERT_ELEM( p_bank->pp_sub, p_bank->i_sub, p_bank->i_sub, p_sub );

    p_sub->i_start = p_bank->i_start;
    p_sub->pi_stop = &p_bank->i_stop;

    p_sub->p_msg   = p_bank->msg;
    p_sub->p_lock  = &p_bank->lock;

    vlc_mutex_unlock( &p_bank->lock );

    return p_sub;
}

/**
 * Unsubscribe from the message queue.
 */
void __msg_Unsubscribe( vlc_object_t *p_this, msg_subscription_t *p_sub )
{
    msg_bank_t *p_bank = &p_this->p_libvlc->msg_bank;
    int i_index;

    vlc_mutex_lock( &p_bank->lock );

    /* Sanity check */
    if( !p_bank->i_sub )
    {
        msg_Err( p_this, "no subscriber in the list" );
        return;
    }

    /* Look for the appropriate subscription */
    for( i_index = 0; i_index < p_bank->i_sub; i_index++ )
    {
        if( p_bank->pp_sub[ i_index ] == p_sub )
        {
            break;
        }
    }

    if( p_bank->pp_sub[ i_index ] != p_sub )
    {
        msg_Err( p_this, "subscriber not found" );
        vlc_mutex_unlock( &p_bank->lock );
        return;
    }

    /* Remove this subscription */
    REMOVE_ELEM( p_bank->pp_sub, p_bank->i_sub, i_index );

    free( p_sub );

    vlc_mutex_unlock( &p_bank->lock );
}

/*****************************************************************************
 * __msg_*: print a message
 *****************************************************************************
 * These functions queue a message for later printing.
 *****************************************************************************/
void __msg_Generic( vlc_object_t *p_this, int i_type, const char *psz_module,
                    const char *psz_format, ... )
{
    va_list args;

    va_start( args, psz_format );
    QueueMsg( p_this, i_type, psz_module, psz_format, args );
    va_end( args );
}

void __msg_GenericVa( vlc_object_t *p_this, int i_type, const char *psz_module,
                      const char *psz_format, va_list args )
{
    QueueMsg( p_this, i_type, psz_module, psz_format, args );
}

/* Generic functions used when variadic macros are not available. */
#define DECLARE_MSG_FN( FN_NAME, FN_TYPE ) \
    void FN_NAME( vlc_object_t *p_this, const char *psz_format, ... ) \
    { \
        va_list args; \
        va_start( args, psz_format ); \
        QueueMsg( (vlc_object_t *)p_this, FN_TYPE, "unknown", \
                  psz_format, args ); \
        va_end( args ); \
    } \
    struct _
/**
 * Output an informational message.
 * \note Do not use this for debug messages
 * \see input_AddInfo
 */
DECLARE_MSG_FN( __msg_Info, VLC_MSG_INFO );
/**
 * Output an error message.
 */
DECLARE_MSG_FN( __msg_Err,  VLC_MSG_ERR );
/**
 * Output a waring message
 */
DECLARE_MSG_FN( __msg_Warn, VLC_MSG_WARN );
/**
 * Output a debug message
 */
DECLARE_MSG_FN( __msg_Dbg,  VLC_MSG_DBG );